View Full Version : Question regarding B737 Radio Tuning Panel

22nd Nov 2016, 17:05
currently I'm developing hardware and software for a B737 RTP for a flight simulator. Question I have is whether their is a default frequency (stby and active) with PWR ON the aircraft or is it the last selected frequency prior shut-down?

Thanks for your help!


23rd Nov 2016, 03:51
There are probably a number of different types. Do you have a manufacturer name and model number? (or at least a picture of the one you intend to model?)

Modern RTPs have non-volatile memories for things such as active/standby frequencies, radio status (active/inactive) for all radios, HF sensitivity for HF radios, AM/SSB mode for HF radios, voice/data mode for VHF and HF radios, high and low brightness settings for one bank of indicators (???)...

I don't know how serious you are about modelling the correct behaviour, but I found this comment in one manufacturer's workshop manuals:

"Non-volatile storage is updated to track changes to any of the above items during normal operation.
... non-volatile memories have a finite number of write cycles (so) the RTP dynamically relocates the information until available space is exhausted. If Non-volatile storage space is exhausted or corrupted in any way, the RTP defaults to the following conditions on power-up:
1. Active and standby frequencies set to 118.00(0) for VHF radios, and to 2800(0) for HF radios.
2. HF sensitivity set to maximum (0 ohms) for HF radios
3. Voice mode for HF radios
4. SSB mode for HF radios"

If I remember correctly, on some aircraft types, where the RTPs talk to each other, the first panel powered up will transfer the tuning data to the other panels (subsequently powering up).

Some RTPs allow you to lock out radios if they are inoperative. This involves pushing two buttons at once during power up. If your simulator doesn't allow multiple inputs at the same time, you may have problems modelling this.

Desktop simulators such as Precision Simulator's "PSX" go to extraordinary lengths to model correct behaviour. Unfortunately, this takes thousands of lines of code to do so (and lots of "experimentation" on real aircraft).


23rd Nov 2016, 17:43
thanks for your reply. Today I could get manual for the G7404 from Gables.